Two-component aqueous compositions containing a water dispersible polyisocyanate component and various water dispersible or water soluble isocyanate-reactive resins, such as polyhydroxy components, are known and described in U.S. Pat. Nos. 5,075,370, 5,389,718, 5,387,642, 5,372,875, 5,336,711, 5,344,873 and 5,459,197. The aqueous compositions may be used for a wide range of commercial applications such as adhesives, sealants or coatings for various substrates including textile fabrics, plastic, wood, glass fibers and metals. Chemical resistance, abrasion resistance, toughness, tensile strength, elasticity and durability are among the many desirable properties of these coatings.
It is known to incorporate alkoxysilane groups into one-component, fully reacted, aqueous polyurethane dispersions. See, e.g., U.S. Pat. Nos. 5,041,494, 5,354,808 and 5,554,686. However, in these patents the alkoxysilane groups are incorporated compounds containing primary amino groups and alkoxysilane groups, such as N-(3-triethoxysilylpropyl) amine. When it is attempted to modify the polyisocyanate component used in two-component aqueous compositions with compounds containing primary amino groups and alkoxysilane groups, the resulting modified polyisocyanates are not dispersible in water.
Accordingly, it is an object of the present invention to provide water dispersible polyisocyanates containing alkoxysilane groups, which are dispersible in water.
This object can be achieved in accordance with the present invention by incorporating the alkoxysilane groups through secondary amino groups.
Copending applications, U.S. Ser. Nos. 08/992,163 and 08/992,551, disclose the preparation of polyurethane-urea dispersions containing alkoxysilane groups incorporated through secondary amino groups, such as aspartate groups. However, the polyurethane dispersions are prepared from monomeric polyisocyanates as opposed to the polyisocyanate adducts required by the subject application.